Rapid thermal processing (or RTP) refers to a semiconductor manufacturing process which quickly heats silicon wafers to high temperatures (up to 1,200° C. or greater) on a timescale of several seconds or less. During cooling, however, wafer temperatures must be brought down slowly to prevent dislocations and wafer breakage due to thermal shock. The rapid heating rates are often attained by high intensity lamps or lasers. RTP is used for a wide variety of applications in semiconductor manufacturing including dopant activation, thermal oxidation, metal reflow and chemical vapor deposition.
Measuring the process temperature is critical for controlling the rapid heating and cooling rates in the RTP tool to prevent damage to the silicon wafers processed therein. Thus, the RPT tool requires a temperature measuring device which has a fast response, is accurate and able to measure temperatures accurately in the temperature range of about 250° C. to 1100° C. Often the ability for the RPT tool to measure the temperature of the substrate quickly and accurately at a relatively low-cost for one end of the temperature range compromises the ability to measure the temperature at the other end of the temperature range.
Therefore, there is a need for an improved temperature measuring device.